26,016 research outputs found
Study on SPH Viscosity Term Formulations
For viscosity-dominated flows, the viscous effect plays a much more important role. Since the viscosity term in SPH-governing (Smoothed Particle Hydrodynamics) equations involves the discretization of a second-order derivative, its treatment could be much more challenging than that of a first-order derivative, such as the pressure gradient. The present paper summarizes a series of improved methods for modeling the second-order viscosity force term. By using a benchmark patch test, the numerical accuracy and efficiency of different approaches are evaluated under both uniform and non-uniform particle configurations. Then these viscosity force models are used to compute a documented lid-driven cavity flow and its interaction with a cylinder, from which the most recommended viscosity term formulation has been identified
Density profiles of supernova matter and determination of neutrino parameters
The flavor conversion of supernova neutrinos can lead to observable
signatures related to the unknown neutrino parameters. As one of the
determinants in dictating the efficiency of resonant flavor conversion, the
local density profile near the MSW resonance in a supernova environment is,
however, not so well understood. In this analysis, variable power-law functions
are adopted to represent the independent local density profiles near the
locations of resonance. It is shown that the uncertain matter density profile
in a supernova, the possible neutrino mass hierarchies, and the undetermined
1-3 mixing angle would result in six distinct scenarios in terms of the
survival probabilities of and . The feasibility of
probing the undetermined neutrino mass hierarchy and the 1-3 mixing angle with
the supernova neutrinos is then examined using several proposed experimental
observables. Given the incomplete knowledge of the supernova matter profile,
the analysis is further expanded to incorporate the Earth matter effect. The
possible impact due to the choice of models, which differ in the average energy
and in the luminosity of neutrinos, is also addressed in the analysis.Comment: 27 pages, 10 figures. text and figures revised, references added, to
appear in Phys. Rev.
Electroweak and QCD corrections to top-pair hadroproduction in association with heavy bosons
We compute the contribution of order to the cross
section of a top-antitop pair in association with at least one heavy Standard
Model boson -- , , and Higgs -- by including all effects of QCD, QED,
and weak origin and by working in the automated MadGraph5_aMC@NLO framework.
This next-to-leading order contribution is then combined with that of order
, and with the two dominant lowest-order ones,
and , to obtain phenomenological results
relevant to a 8, 13, and 100~TeV collider.Comment: 27 pages, 8 figure
Gisin's Theorem for Arbitrary Dimensional Multipartite States
We present a set of Bell inequalities which are sufficient and necessary for
separability of general pure multipartite quantum states in arbitrary
dimensions. The relations between Bell inequalities and distillability are also
studied. We show that any quantum states that violate one of these Bell
inequalities are distillable.Comment: 5 page
Multi-Source Multi-View Clustering via Discrepancy Penalty
With the advance of technology, entities can be observed in multiple views.
Multiple views containing different types of features can be used for
clustering. Although multi-view clustering has been successfully applied in
many applications, the previous methods usually assume the complete instance
mapping between different views. In many real-world applications, information
can be gathered from multiple sources, while each source can contain multiple
views, which are more cohesive for learning. The views under the same source
are usually fully mapped, but they can be very heterogeneous. Moreover, the
mappings between different sources are usually incomplete and partially
observed, which makes it more difficult to integrate all the views across
different sources. In this paper, we propose MMC (Multi-source Multi-view
Clustering), which is a framework based on collective spectral clustering with
a discrepancy penalty across sources, to tackle these challenges. MMC has
several advantages compared with other existing methods. First, MMC can deal
with incomplete mapping between sources. Second, it considers the disagreements
between sources while treating views in the same source as a cohesive set.
Third, MMC also tries to infer the instance similarities across sources to
enhance the clustering performance. Extensive experiments conducted on
real-world data demonstrate the effectiveness of the proposed approach
The automation of next-to-leading order electroweak calculations
We present the key features relevant to the automated computation of all the
leading- and next-to-leading order contributions to short-distance cross
sections in a mixed-coupling expansion, with special emphasis on the first
subleading NLO term in the QCD+EW scenario, commonly referred to as NLO EW
corrections. We discuss, in particular, the FKS subtraction in the context of a
mixed-coupling expansion; the extension of the FKS subtraction to processes
that include final-state tagged particles, defined by means of fragmentation
functions; and some properties of the complex mass scheme. We combine the
present paper with the release of a new version of MadGraph5_aMC@NLO, capable
of dealing with mixed-coupling expansions. We use the code to obtain
illustrative inclusive and differential results for the 13-TeV LHC.Comment: 121 pages, 16 figure
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